Maybe it would work, but the apps are only being offered to in the case of the one I found Porsche only owner will be given access to the app, it would seem if a Porsche owner also had a Vauxhall he could charge his Vauxhall, but by restricting the app, they are getting around the new law.
Imagine if Shell only refuelled Vauxhall diesels, and BP limited themselves to refuelling Fords